As an infant, Willamar was snatched by a golden eagle, which attempted to carry him off. His mother saw what was happening and grabbed hold of him, managing to pull him away from the eagle, though the bird's talons scratched him deeply, leaving permanent scars. According to the beliefs of his people, the spirit of the Golden Eagle had marked Willamar as its own and he was able to claim the Golden Eagle as his personal totem.
Willamar, who enjoyed travelling, became a trader, eventually becoming Trade Master of the Ninth Cave. He travelled all over the Zelandonii territory and beyond, trading goods. He occasionally encountered Neanderthals, whom the Zelandonii call "flat-heads" and, unlike the majority of his people, came to realise they were not animals, but another type of human, though he kept this knowledge to himself, as no one ever brought it up. Willamar eventually became the third mate of Marthona, not long after she severed the knot with Dalanar. Willamar became the "man of the hearth' to her son Jondalar and also had two more children with her.
Folara and Thonolan are hinted to be the "children of his spirit", though it does not seem to be of much consequence to him whether his children are of "his spirit" or not, as he feels a fatherly love for Jondalar and Ayla as well. His relationship with Marthona's eldest son Joharran is more one of friendship, as Joharran had reached manhood when he mated with Marthona.
- In Willamar's first mention in The Valley of Horses, and in the next two novels, his name is stated as being Willomar. However, from The Shelters of Stone onwards, his name is stated as being Willamar. It is unknown why this change occured.